Color me skeptical. A prison environment (full of "shenanigans", we'll say) is not the same as an assisted-suicide environment, and I'd bet there are other factors involved. (The article mentions several, like the secrecy around the executions, the source of the N, and even the administration method:
"In both Georgia and Texas, placing IVs in the arms of inmates who had been heavy drug users caused some difficulty. Atlanta Journal-Constitution reporter Rhonda Cook said in the case of one execution, the team 'couldn't get a vein', and what they had to do is what they call a 'cut down' where they inserted the IV at the base of his neck."
or this:
"And in 2015, Georgia had to cancel a scheduled execution because the pentobarbital was stored at too cold of a temperature. 'And what happened was the solids that are combined with the liquid to create pentobarbital separated. So there were clumps in the containers that had the pentobarbital,' Cook said."
If it were truly an issue, would the PPH still be promoting it as a "peaceful pill", and would people would not still be seeking it out as a holy grail?
I've seen the videos of people drinking it and falling to sleep in minutes, so my guess is "no".
As for whether it was N alone or as part of a cocktail: According to this article :
"When Donald Trump's Justice Department announced in 2019 it'd resume executions after a 17-year hiatus, it said it would use pentobarbital alone. Manufacturers were no longer willing to supply the combination of drugs used in three federal executions from 2001 to 2003, explaining they didn't want drugs meant to save lives to be used for killing."
The sworn accounts raise questions about whether officials misled courts in order to ensure executions happened before Joe Biden's inauguration.
www.indystar.com